The longer the cooldown of an ability the less that ability actually affects your gameplay. I don't care about the power level changing with increased cooldowns, I care that a tool used to (potentially) create a more varied moment-to-moment gameplay is being taken away.
Big flashy effects like the legendary abilities are kinda cool, but they don't change how we play.
To me this sounds like a further simplification of the core combat loop when one of the greatest problems with Dauntless's gameplay has always been how stale it got. I deeply hope that increased cooldowns on any form of anything is rethought. I have had a years long addition to the Koshai Lantern because it has an active and significant effect on my playstyle, it doesn't matter if there is a number-go-up, taking away a tool I use to deepen combat will directly decrease my fun.
Again, this isn't about numbers, it isn't about balance, increased cooldowns are a reduction to the potential variation...